Beta arrestin1 associated genomic regions in nicotine induced Non-Small Cell Lung Carcinoma (NSCLC) cell line A549

The multifunctional scaffolding protein ß-arrestin-1 plays a vital role in mediating the proliferative effects of nicotine through nAChR signaling. ß-arrestins were initially known as negative regulators of GPCR mediated signaling as they promote internalization and desensitization of GPCRs. However, new roles of ß-arrestins in receptor trafficking and signaling have been discovered in recent years. They are known to regulate signaling through a number of receptors such as Notch, endothelin A receptor, frizzled, smoothened and the nicotinic cholinergic receptors. Studies from our lab revealed that nAChR signaling induces the translocation of ß-arrestin-1 to the nucleus, in a Src dependent manner, where it directly binds to the proliferative E2Fs. Furthermore, the nuclear translocation of ß-arrestin-1 results in recruitment of p300 to E2F1 regulated proliferative promoters facilitating histone acetylation and transcription of these promoters. Given the role of ß-arrestin-1 in nicotine induced gene expression, we attempted to explore the global association of ß-arrestin-1 to the genomic regions upon nicotine stimulation by ChIP sequencing. It was found that ß-arrestin-1 is recruited on the promoters of many genes that regulate EMT as well as other regulatory pathways. In this assay, ß-arrestin-1 was found to be associated with the promoter regions of genes such as ZNF768, ZNF131, CSF3R, HMGA2, TAL1, RCC1, NKX2-4 etc in response to nicotine stimulation. Overall design: Serum starved/quiescent A549 cells and Nicotine stimulated A549 cells